deny command is used to deny a suggestion and if configured, move it to the denied suggestion channel.
# Suggestion IDs are found in footer of existing suggestions
z/deny UYAWV # by suggestion ID, no reason
z/deny UYAWV Because # by suggestion ID, with a reason
z/deny 591200899255500840 # by message ID, no reason
z/deny 591200899255500840 Because # by message ID, with a reason
See the Discord help page Where can I find my User/Server/Message ID? for instructions on how to find a message ID.